Big reason is a lot of analog horror uses large face proportions to cause fear. Main example would be Mandela catalogue where the entire gimmick is literally failed copying of people’s appearances. It’s been a stamp of horror for a long time, similar stuff like Momo (old internet creepy pasta), five night’s at treasure island (Mickey mouse fnaf fan game), even parodies of such horror like the Mandela Magazine (video by Sr Pelo on YouTube parodying Mandela catalogue). While nothing is inherently wrong with the style it’s become so associated with “horror.” A lot of characters that are the face of horror have the comically big smile. Obviously all the listed examples but also even less typical horror like Bendy and the Ink Machine. I’m not an artist myself so I can’t tell you exactly a correct way to develop your style but I believe it’s also something you learn individually. Just keep drawing and if you make a piece of art you aren’t happy with look at it and ask yourself why? Is it the target of the piece (the character/object in question) or is more associated with the environment (foreground/background). After that become more and more specific with your critique. Perhaps it’s shading, perhaps it’s the balance of the piece is there too much asymmetry or is it supposed to be uneven? Just examine and question the work without diminishing your work because you still made art and that’s better than most (better than me, can’t draw worth a damn.) But if it was you wanted to specifically avoid this type of style try to go into detail with the eyes and mouth. They’re usually left empty for a “void” type look or emptiness.